The ultrastructural characteristics and pathophysiological reactions of various diseased corneas (especially the corneal dystrophies) are being studied with all appropriate techniques that are currently employed in modern well equipped pathology departments. The techniques include in vivo microscopy, various types of light (e.q. phase contrast, fluorescence, and polarized light, interference) and electron microscopy, established light and electron microscopic histochemical and cytochemical methods (including those for glycosaminoglycals, collagen, and various enzymes that are associated with specific cells or cell organelles), light and electron microscopic autoradiography, and immunologic methods. The morphology and biochemical behavior of the cellular elements of normal and dystrophic corneas are being investigated in cell culture. The nature of the metabolic defect of the corneal cellular elements in genetically determined corneal diseases is being sought employing cell culture techniques. The rate of incorporation and degradation of labelled precursors by corneal cells is being studied. A genetic and genealogic study is being performed on inherited corneal diseases occurring in the southeastern United States. The pedigrees of all known cases of macular corneal dystrophy are being traced back to a common ancestor. The pathogenesis of corneal vascularization is being investigated in a variety of experimental models. These studies are based upon a systematic investigation of the biological properties of the cornea and those factors inducing vascularity with particular attention to those of clinical significance.